Three Weeks of Inpatient Cardiac Rehabilitation Improves Metabolic Exercise Data Combined With Cardiac and Kidney Indexes Scores for Heart Failure With Reduced Ejection Fraction.

Background: Heart failure with reduced ejection fraction (HFrEF) has a high mortality rate, and cardiac rehabilitation programs (CRP) reduce HFrEF rehospitalization and mortality rates. Some countries attempt 3 weeks of inpatient CRP (3w In-CRP) for cardiac diseases. However, whether 3w In-CRP reduces the prognostic parameter of the Metabolic Exercise data combined with Cardiac and Kidney Indexes (MECKI) score is unknown. Therefore, we investigated whether 3w In-CRP improves MECKI scores in patients with HFrEF. Methods and Results: This study enrolled 53 patients with HFrEF who participated in 30 inpatient CRP sessions, consisting of 30 min of aerobic exercise twice daily, 5 days a week for 3 weeks, between 2019 and 2022. Cardiopulmonary exercise tests and transthoracic echocardiography were performed, and blood samples were collected, before and after 3w In-CRP. MECKI scores and cardiovascular (CV) events (heart failure rehospitalization or death) were evaluated. The MECKI score improved from a median 23.34% (interquartile range [IQR] 10.21-53.14%) before 3w In-CRP to 18.66% (IQR 6.54-39.94%; P<0.01) after 3w In-CRP because of improved left ventricular ejection fraction and percentage peak oxygen uptake. Patients' improved MECKI scores corresponded with reduced CV events. However, patients who experienced CV events did not have improved MECKI scores. Conclusions: In this study, 3w In-CRP improved MECKI scores and reduced CV events for patients with HFrEF. However, patients whose MECKI scores did not improve despite 3w In-CRP require careful heart failure management.

Differential Impact of Renal Function on the Diagnostic Performance of Resting Full-Cycle Ratio in Patients With Renal Dysfunction.

Background: Physiological assessments using fractional flow reserve (FFR) and resting full-cycle ratio (RFR) have been recommended for revascularization decision making. Previous studies have shown a 20% rate of discordance between FFR and RFR. In this context, the correlation between RFR and FFR in patients with renal dysfunction remains unclear. This study examined correlations between RFR and FFR according to renal function. Methods and Results: In all, 263 consecutive patients with 370 intermediate lesions were enrolled in the study. Patients were classified into 3 groups according to renal function: Group 1, estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2; Group 2, 30 mL/min/1.73 m2≤eGFR<60 mL/min/1.73 m2; Group 3, eGFR <30 mL/min/1.73 m2. The discordance between FFR and RFR was assessed using known cut-off values for FFR (≤0.80) and RFR (≤0.89). Of the 370 lesions, functional significance with FFR was observed in 154 (41.6%). RFR was significantly correlated with FFR in all groups (Group 1, R2=0.62 [P<0.001]; Group 2, R2=0.67 [P<0.001]; Group 3, R2=0.46 [P<0.001]). The rate of discordance between RFR and FFR differed significantly among the 3 groups (Group 1, 18.8%; Group 2, 18.5%; Group 3, 42.9%; P=0.02). Conclusions: The diagnostic performance of RFR differed based on renal function. A better understanding of the clinical factors contributing to FFR/RFR discordance, such as renal function, may facilitate the use of these indices.

Diagnostic Performance of High-Resolution Intravascular Ultrasound for Abnormal Post-Stent Findings After Stent Implantation　- A Comparison Study Between High-Resolution Intravascular Ultrasound and Optical Coherence Tomography.

BACKGROUND: High-resolution intravascular ultrasound (HR-IVUS) is the most recently developed IVUS technology, which allows the detailed assessment of intravascular structures. The aim of this study was to evaluate the diagnostic performance of HR-IVUS in the detection of abnormal post-stent findings.Methods and Results:Patients with acute coronary syndrome underwent both HR-IVUS and optical coherence tomography (OCT) for post-stent evaluations. Quantitative measurements for stented segments and qualitative assessments for abnormal post-stent findings (stent edge dissection, intrastent tissue protrusion, and incomplete stent apposition [ISA]) were performed. Forty-seven patients underwent both HR-IVUS and OCT after stent implantation. HR-IVUS identified a larger minimal lumen area and a larger minimal lumen diameter than OCT (6.66±1.98 mm2vs. 5.61±1.79 mm2and 2.87±0.42 mm vs. 2.63±0.43 mm, respectively; both P<0.001). The sensitivity of HR-IVUS for the identification of stent edge dissection, intrastent tissue protrusion, and ISA were 20.0%, 48.9%, and 27.2%, respectively. CONCLUSIONS: In terms of post-stent evaluation, the diagnostic performance of HR-IVUS remains insufficient. Abnormal post-stent findings might be underestimated when performing HR-IVUS due to its low sensitivity.

Independent predictors of discordance between the resting full-cycle ratio and fractional flow reserve.

The resting full-cycle ratio (RFR), a novel resting index, is well correlated with and shows good diagnostic accuracy to the fractional flow reserve (FFR). However, discordance results between the RFR and FFR have been observed to occur in about 20% of cases. This study aimed to clarify the prevalence and factors of discordant results between the RFR and FFR through a direct comparison of these values in daily clinical practice. A total of 220 intermediate coronary lesions of 156 consecutive patients with RFR and FFR measurements were allocated to four groups according to RFR and FFR cutoff values. We compared the angiographic, clinical, and hemodynamic variables among the groups. Discordant results between the RFR and FFR were observed in 19.6% of vessels, and the proportion of discordant results was significantly higher in the left main trunk and left anterior descending artery (LM + LAD) than in non-LAD vessels (25.2% vs. 12.3%, p = 0.006). In the multivariable regression analysis, LM + LAD location, hemodialysis, and peripheral artery disease were associated with a low RFR among patients with a high FFR. Conversely, the absence of diabetes mellitus and the presence of higher hemoglobin levels were associated with a higher RFR among patients with a low FFR. Specific angiographic and clinical characteristics such as LM + LAD location, hemodialysis, peripheral artery disease, and absence of diabetes mellitus and anemia can be independent predictors of physiologic discordance between the RFR and FFR.

Impact of antiplatelet therapy on tissue prolapse at super acute phase after stenting: serial OCT study in acute coronary syndrome patients.

Although drug-eluting stents have improved clinical outcomes, percutaneous coronary intervention (PCI) for acute coronary syndrome (ACS) remains a challenging procedure in terms of thrombus management. A new-generation P2Y12 receptor inhibitor, prasugrel, provides more rapid and potent antiplatelet action compared with clopidogrel. Prasugrel achieved significant reduction of ischemic events compared with clopidogrel in ACS. The aim of this optical coherence tomography (OCT) study was to evaluate temporal changes in tissue prolapse after stenting under different antiplatelet regimens (aspirin plus prasugrel or clopidogrel) in ACS patients. A total of 119 ACS patients were randomized to either prasugrel or clopidogrel at the time of PCI. OCT analysis was available in 119 patients at baseline (just after stenting), 77 patients at 2 weeks, and 62 patients at 4 months after stenting. Cross-sectional analysis for every 1 mm was performed at in-stent and adjacent reference segment. Tissue prolapse area was calculated by lumen area minus stent area within the stented segment. Baseline patient and procedural characteristics were not different between the prasugrel and clopidogrel groups. Tissue prolapse area was significantly lower in the prasugrel compared with the clopidogrel group after stenting (0.24 ± 0.23 vs. 0.36 ± 0.23 mm2, p = 0.003) and at 2 weeks (0.11 ± 0.13 vs. 0.19 ± 0.16 mm2, p = 0.005). However, there was no significant difference at 4 months. In conclusion, our study suggests prasugrel was effective in reducing tissue prolapse in the super acute phase in ACS patients compared with clopidogrel. However, the effect of tissue prolapse reduction was not different up to 4 months follow-up.

Temporal changes of incomplete stent apposition during early phase after everolimus-eluting stent implantation: serial optical coherence tomography analyses at 2-week and 4-month.

The healing process of acute incomplete stent apposition (ISA) in the early phase after stent implantation has not been well understood. We evaluated the temporal changes of ISA during the early phase after everolimus-eluting stent (EES) implantation using serial optical coherence tomography (OCT) analyses. Serial OCT examinations were performed immediately post-stenting and 2-week and 4-month after EES implantation for patients with ST-segment elevation myocardial infarction. At the most proximal cross-section of the implanted stent, the prevalence of ISA and maximum ISA distance were serially evaluated. In 45 patients with ST-segment elevation myocardial infarction, serial OCT analyses at 2-week and 4-month were performed. The prevalence of ISA gradually decreased over time, being 53.3% at baseline, 37.8% at 2-week follow-up, and 11.1% at 4-month follow-up (P < 0.001). The maximum ISA distance also decreased over time (P < 0.001). A receiver-operating curve analysis found that the optimal cut-off values of the baseline ISA distance for predicting persistent ISA at 2-week follow-up and 4-month follow-up were > 140 µm and > 215 µm, respectively. The baseline ISA distance was closely associated with the healing of ISA in the early phase after EES implantation. Maintaining the minimum ISA distance at post-stenting facilitates early phase healing of acute ISA.

Prevalence and clinical outcomes of triglyceride deposit cardiomyovasculopathy among haemodialysis patients.

OBJECTIVE: To evaluate the effect of triglyceride deposit cardiomyovasculopathy (TGCV) on the cardiovascular outcomes in haemodialysis (HD) patients with suspected coronary artery disease (CAD). METHODS: This retrospective single-centre observational study included data from the cardiac catheter database of Narita Memorial Hospital between April 2011 and March 2017. Among 654 consecutive patients on HD, the data for 83 patients with suspected CAD who underwent both [123I]-ß-methyl-iodophenyl-pentadecanoic acid scintigraphy and coronary angiography were analysed. Patients were divided into three groups: definite TGCV (17 patients), probable TGCV (22 patients) and non-TGCV control group (44 patients). The primary endpoint was a composite of cardiovascular death, non-fatal myocardial infarction and non-fatal stroke assessed for up to 5 years of follow-up. RESULTS: The prevalence of definite TGCV was approximately 20% and 2.6% among consecutive HD patients with suspected CAD and among all HD patients, respectively. At the end of the median follow-up period of 4.7 years, the primary endpoint was achieved in 52.9% of the definite TGCV patients (HR, 7.45; 95% CI: 2.28 to 24.3; p<0.001) and 27.3% of the probable TGCV patients (HR, 3.28; 95% CI: 0.93 to 11.6; p=0.066), compared with that in 9.1% of the non-TGCV control patients. Definite TGCV was significantly and independently associated with cardiovascular mortality and outcomes among HD patients in all multivariate models. CONCLUSIONS: TGCV is not uncommon in HD patients and is associated with an increased risk of cardiovascular events including cardiovascular death. Thus, TGCV might be a potential therapeutic target.

Clinical feasibility of resting full-cycle ratio as a unique non-hyperemic index of invasive functional lesion assessment.

The resting full-cycle ratio (RFR) is a new physiologic index to assess myocardial ischemia. RFR and fractional flow reserve (FFR), the conventionally used index, have not been directly compared in evaluating the entire cardiac cycle. Accordingly, we aimed to compare the diagnostic performance of RFR directly with FFR and clarify the clinical feasibility of RFR as a unique non-hyperemic index in evaluating the cardiac cycle. The diagnostic performance of RFR was compared with FFR using an automated online calculation software. A total of 156 consecutive patients with 220 intermediate lesions were enrolled. RFR showed significant correlation with FFR (r = 0.774, p < 0.001). RFR systole and RFR diastole did also with FFR (r = 0.918, p < 0.001, and r = 0.733, p < 0.001, respectively). With FFR < 0.80 as a reference standard, RFR showed good diagnostic accuracy (DA: 80.5%), similar DA between RFR systole and RFR diastole (79.6% and 87.5%, p = 0.58, respectively), and good DA in any lesion locations, especially in non-left anterior descending coronary artery (LAD) lesions (73.7% and 87.6% for LAD vs. non-LAD, p < 0.05, respectively). RFR is a feasible and reliable non-hyperemic index regardless of the difference in cardiac cycle in evaluating physiological lesion severity in daily practice.

Epidemiological Features and Clinical Presentations of Acute Coronary Syndrome in Young Patients.

Objective Although acute coronary syndrome (ACS) is an uncommon entity in young patients, it constitutes an important problem due to the devastating effects of the disease on the more active lifestyle of young patients. At present, there are no guidelines regarding the prevention of ACS in young patients. Methods We performed a retrospective study of ACS patients between 2014 and 2017. Epidemiological data, clinical findings, and short-term outcomes were evaluated between young ACS patients (≤50 years old) and elderly ACS patients (>50 years old). Results Of a total of 361 consecutive ACS patients, 37 were young ACS patients (10.2%). Compared with elderly ACS patients, young ACS patients showed a higher prevalence of males (94.6% vs. 73.8%, p<0.001), current smoking (70.3% vs. 29.9%; p<0.001), and overweight persons (67.6% vs. 27.8%, p<0.001). The eicosapentaenoic acid (EPA)/arachidonic acid (AA) ratio was significantly lower in young ACS patients than in elderly ACS patients [0.17 (0.12-0.25) vs. 0.25 (0.18-0.37), p=0.002]. The prevalence of cardio-pulmonary arrest and percutaneous cardiopulmonary support use was higher in young ACS patients than in elderly ACS patients (24.3% vs. 8.6%, p=0.003, 16.2% vs. 3.1%, p<0.001). Conclusion The features were markedly different between young ACS patients and elderly ACS patients. In young ACS patients, smoking, being overweight, and a low EPA/AA ratio were distinctive risk factors, and more serious clinical presentations were observed at the onset of ACS than in older patients.

Clinical comparison study between a newly developed optical-based fractional flow reserve device and the conventional fractional flow reserve device.

BACKGROUND: Fractional flow reserve (FFR) measurement is the gold standard for identifying the functional severity of coronary artery disease. Although we can use newly developed pressure wires with optical fibers are now available, their safety and accuracy for FFR measurement are not clear. Therefore, we planned a clinical comparison study between pressure wires with optical fibers and the conventional FFR device. METHODS: We prospectively enrolled 51 patients (51 lesions) with intermediate coronary artery stenosis. For these lesions, FFR measurements with pressure wires with optical fibers were compared with those obtained with a conventional wire. RESULTS: All procedures were successfully completed without any complications. The procedure time with pressure wires with optical fibers and a conventional wire was 6.8 ± 3.0 and 6.9 ± 2.6 minutes (P = 0.89), respectively. There was no significant difference in FFR values between pressure wires with optical fibers and a conventional wire (0.83 ± 0.10 vs. 0.83 ± 0.12, P = 0.66). An excellent correlation was observed between FFR obtained with pressure wires with optical fibers and FFR obtained with a conventional wire (r = 0.81, P < 0.001). The pressure drift before and after FFR measurements was not significantly different between pressure wires with optical fibers and a convention wire (-0.01 ± 0.02 vs. -0.02 ± 0.06, P = 0.42). There was no significant difference in pressure drift defined as >0.03 or <-0.03 between pressure wires with optical fibers and a convention wire (13.7 vs. 17.6%, P = 0.79). CONCLUSION: Excellent correlations were observed between FFR values measured using pressure wires with optical fibers and a conventional wire. Furthermore, measurement of FFR with pressure wires with optical fibers was as well tolerated and reliable as that with a conventional wire.

Diagnostic Performance of High-Resolution Intravascular Ultrasound for the Detection of Plaque Rupture in Patients With Acute Coronary Syndrome.

BACKGROUND: The new 60-MHz high-resolution intravascular ultrasound (HR-IVUS) is the next-generation IVUS technology, providing higher image resolution than conventional IVUS. It gives clear images of plaque morphology and can discriminate the underlying mechanism of acute coronary syndrome (ACS). Our study aimed to evaluate the diagnostic performance of 60-MHz HR-IVUS in the detection of plaque rupture in patients with ACS.Methods and Results:Patients with ACS who underwent percutaneous coronary intervention for de novo native coronary artery lesions were enrolled. Both HR-IVUS and optical coherence tomography (OCT) were performed for the culprit lesions prior to interventions other than aspiration thrombectomy. Keeping plaque rupture detected by OCT as the gold standard, the diagnostic performance of HR-IVUS was evaluated. Overall, 70 patients underwent both HR-IVUS and OCT examinations. Of these, imaging assessments by HR-IVUS were available for all 70 patients (100%), and those by OCT were available for 54 patients (77.1%). Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of HR-IVUS for identifying a plaque rupture were 84.8%, 57.1%, 75.7%, 70.6%, and 74.1%, respectively. CONCLUSIONS: HR-IVUS had high sensitivity, but modest specificity for identifying OCT-derived plaque rupture. Compared with results from previous conventional IVUS studies, HR-IVUS might have increased ability to detect OCT-derived plaque rupture, but there is still substantial scope for improvement, especially in the specificity.

Early-Phase Vascular Healing of Bioabsorbable vs. Durable Polymer-Coated Everolimus-Eluting Stents in Patients With ST-Elevation Myocardial Infarction　- 2-Week and 4-Month Analyses With Optical Coherence Tomography.

BACKGROUND: Despite the revolution of coronary stents, there remain concerns about the risk of stent thrombosis, especially in patients with ST-elevation myocardial infarction (STEMI). The present study compared early vascular healing as a contributing factor to reducing stent thrombosis between Xience everolimus-eluting stents (X-EES) and Synergy everolimus-eluting stents (S-EES) in patients with STEMI. Methods and Results: The present study included 47 patients with STEMI requiring primary percutaneous coronary intervention with X-EES (n=25) or S-EES (n=22). Optical coherence tomography (OCT) assessments of the stented lesions were performed 2 weeks and 4 months after stent implantation. Neointimal strut coverage, malapposition and the frequency of thrombus formation were evaluated. In the 2-week OCT analysis, the proportion of covered struts in S-EES (42.4±15.4%) was significantly higher than in X-EES (26.3±10.1%, P<0.001). In the 4-month OCT analysis, the proportion of covered struts in S-EES (72.2±17.9%) was still significantly higher than in X-EES (62.0±14.9%, P=0.04). CONCLUSIONS: Compared with X-EES, S-EES showed a higher proportion of covered struts in the early phase after stent implantation for STEMI patients.

Tissue characteristics of neointima in late restenosis: integrated backscatter intravascular ultrasound analysis for in-stent restenosis.

Although late restenosis is one of the long-term complications of stent implantation, its pathogenesis has not been fully elucidated. For consecutive patients who developed in-stent restenosis (ISR) after stent implantation, integrated backscatter (IB) intravascular ultrasound was performed for ISR lesions. The tissue characteristics of neointima within the stented segment were compared between lesions with early restenosis and those with late restenosis. Of 73 ISR lesions arising after sirolimus-eluting stent (SES; n = 25) or bare-metal stent (BMS; n = 48) implantation, early and late restenosis were documented in 52 and 21 lesions, respectively. A higher prevalence of late restenosis was observed after SES implantation than after BMS implantation (60.0 vs. 12.5 %; p < 0.001). The duration between stent implantation and late restenosis was significantly shorter after SES implantation than after BMS implantation (57.0 ± 22.1 vs. 124.4 ± 19.6 months; p < 0.001). Percent low-IB volume was significantly higher in the neointima of late restenosis than in that of early restenosis (29.9 ± 9.9 vs. 19.8 ± 11.3 %; p < 0.001). Significantly more low-IB tissue was observed in the neointima of late restenosis than in that of early restenosis, suggesting atherosclerotic progression in late phase after stent implantation as a possible mechanism of late restenosis.

Impact of lesion characteristics on the prediction of optimal poststent fractional flow reserve.

BACKGROUND: Poststent fractional flow reserve (FFR) is a useful indicator of optimal percutaneous coronary intervention, and higher poststent FFR is associated with favorable long-term clinical outcome. However, little is known about the factors influencing poststent FFR. The purpose of this study was to determine the impact of lesion characteristics on poststent FFR. METHODS: For patients who had scheduled stent implantation for stable angina, FFR measurements at maximum hyperemia were performed before and after coronary stent implantation. As one of lesion characteristics, the FFR pressure drop pattern was evaluated and classified as either an abrupt or a gradual pattern according to the pullback curve of FFR. RESULTS: A total of 205 lesions with physiological significant stenosis were evaluated. Fractional flow reserve value increased from 0.67±0.10 to 0.87±0.07 after stent implantation. Optimal poststent FFR was achieved in 75 lesions (36.6%). Logistic regression analysis demonstrated that optimal poststent FFR was positively correlated with an abrupt pressure drop pattern (hazard ratio [HR] 2.11, 95% CI 1.06-4.15, P=.03) and prestent FFR (HR 1.04, 95% CI 1.03-2.04, P=.03; per 0.1 increase), and negatively correlated with lesion localization to the left anterior descending artery (HR 0.18, 95% CI 0.09-0.36, P<.0001). The c statistic for predicting optimal poststent FFR was 0.763 (95% CI 0.702-0.819). CONCLUSION: Abrupt pressure drop patterns, prestent FFR, and lesion localization to the left anterior descending artery were independent predictors of optimal poststent FFR.

Influence of plaque characteristics on fractional flow reserve for coronary lesions with intermediate to obstructive stenosis: insights from integrated-backscatter intravascular ultrasound analysis.

The aim of this study was to determine the correlation between the fractional flow reserve (FFR) values and volumetric intravascular ultrasound (IVUS) parameters derived from classic gray-scale IVUS and integrated backscatter (IB)-IVUS, taking into account known confounding factors. Patients with unstable angina pectoris with the frequent development of vulnerable plaques often showed the discrepancy between the FFR value and the quantitative coronary angiography findings. Our target population was 107 consecutive subjects with 114 isolated lesions who were scheduled for elective coronary angiography. The FFR was calculated as the mean distal coronary pressure divided by the mean aortic pressure during maximal hyperemia. Various volumetric parameters such as lipid plaque volume (LPV) and percentage of LPV (%LPV) were measured using IB-IVUS. Simple and multivariate linear regression analysis was employed to evaluate the correlation between FFR values and various classic gray-scale IVUS and IB-IVUS parameters. The Akaike information criterion (AIC) was used to compare the goodness of fit in an each model. Both the %LPV (r = -0.24; p = 0.01) and LPV (r = -0.40; p < 0.01) were significantly correlated with the FFR value. Only the LPV (AIC = -147.0; p = 0.006) and %LPV (AIC = -152.9; p = 0.005) proved to be independent predictors for the FFR value even after the adjustment of known confounding factors. The volumetric assessment by IB-IVUS could provide better information in terms of the relationship between plaque morphology and the FFR values as compared to the classic IVUS 2-dimensional gray-scale analysis.

Severity of morphological lesion complexity affects fractional flow reserve in intermediate coronary stenosis.

BACKGROUND: Although functional ischemia identification is important when determining revascularization, angiographic assessment alone is challenging in intermediate coronary stenosis. Previous studies have reported that lesion-specific characteristics affected the fractional flow reserve (FFR). However, the relationship between morphological lesion complexity and FFR has not yet been fully evaluated. This study aimed to evaluate the impact of morphological lesion complexity on FFR in intermediate coronary stenosis. METHODS: A total of 109 consecutive patients with 136 intermediate coronary stenoses (visually estimated diameter stenosis: 40-70%) were assessed via quantitative coronary angiography, lesion-specific characteristics, and FFR. Indexed lesions were assessed according to 6 morphological lesion characteristics: eccentricity, bend, irregularity, calcification, bifurcation, and diffuse. The lesions were then classified into 3 groups according to the morphological severity count represented by the number of present characteristics (mild-complex: 0-1, moderate-complex: 2-3, and severe-complex: 4-6), and their functional severities were evaluated. Lesions with an FFR <0.80 were considered functionally significant coronary stenoses. RESULTS: Of the 136 lesions, 51% were located in the left anterior descending artery (LAD) and 47% had an FFR <0.80. The FFR differed significantly among the 3 lesion complexity groups (0.84±0.10 vs. 0.79±0.10 vs. 0.73±0.07, for mild-, moderate-, and severe-complex, respectively; p<0.01). In a multivariate logistic analysis, LAD lesions, moderate- and severe-complex, and diameter stenosis were independently associated with an FFR <0.80 [odds ratio (OR): 5.65, 95% confidence interval (CI): 2.50-12.80, p<0.01; OR: 2.96, 95% CI: 1.30-6.72, p<0.01; OR: 7.11, 95% CI: 1.25-40.37, p=0.03, and OR: 2.65, 95% CI: 1.04-6.72, p=0.04, respectively]. CONCLUSIONS: Both indexed vessels and the degree of diameter stenosis affected the FFR. In addition, the severity of morphological lesion complexity correlated with the degree of functional severity in intermediate coronary stenosis.

Feasibility and safety of intracoronary nicorandil infusion as a novel hyperemic agent for fractional flow reserve measurements.

Fractional flow reserve (FFR) is a useful modality to assess the functional significance of coronary stenoses. Although adenosine triphosphate (ATP) is generally used as the hyperemic stimulus, we sometimes encounter adverse events like hypotension during FFR measurement. Nicorandil, an ATP-sensitive potassium channel opener, recognized as an epicardial and resistance vessel dilator, has not been fully evaluated as a possible alternative hyperemic agent. The aim of this study was to evaluate the feasibility and safety of intracoronary nicorandil infusion compared to intravenous ATP for FFR measurement in patients with coronary artery disease. A total of 102 patients with 124 intermediate lesions (diameter stenosis >40 and <70% by visual assessment) were enrolled. All vessels underwent FFR measurements with both ATP (150 µg/kg/min) and nicorandil (2.0 mg) stimulus. FFR, hemodynamic values, and periprocedural adverse events between the two groups were evaluated. A strong correlation was observed between FFR with ATP and FFR with nicorandil (r = 0.954, p < 0.001). The agreement between the two sets of measurements was also high, with a mean difference of 0.01 ± 0.03. The mean aortic pressure drop during pharmacological stimulus was significantly larger with ATP compared to nicorandil (9.6 ± 9.6 vs. 5.5 ± 5.8 mmHg, p < 0.001). During FFR measurement, transient atrioventricular block was frequently observed with ATP compared to nicorandil (4.0 vs. 0%, p = 0.024). This study suggests that intracoronary nicorandil infusion is associated with clinical utility and safety compared to ATP as an alternative hyperemic agent for FFR measurement.